Electric "table top" water heater.

I'm considering buying a 40 gallon electric "table top" water heater to replace a 30 gallon heater that is under the kitchen countertop of my vacation apartment in Florida. I've found models by Rheem, Maytag, Sears, A.O. Smith, State Industries and American Water Heater. They are 36" high and 25" wide (Rheem) with a first hour rating G.P.H. of 45 and look kind of like a dish washer. The water inlets and outlets, relief valve and eletrical conections are at the top for "easy access and fast installation."
I'd like opinions about how much more hot water this 40 gallon heater would give me than the 30 gallon heater. How it would look inserted into the kitchen counter as opposed to the hidden 30 gallon model. Which brand you recommend and any other comments.
Thanks a lot.

Typically, all of the specs are on the company's website. Look for first hour delivery rate, and recovery rates. You can get an idea if you want to do some math...a gallon of water is approximatley 8 pounds. If you figure the flow rate in gallons/minute, you can get the weight of the water you want to heat. Then figure how many degrees it needs to raise the temp. A BTU is one pound/one degree (typically) per hour. A BTU/minute = 17.569W. So 3 gallons/minute = 24 pounds. If you need to raise it from 50 degrees to 110, that's 60 degrees. 60*24*17.569 = 25,299W. The thing is probably only about 2-3 Kw, so the water you used in one minute would take about 12-13 minutes to reheat. I haven't double-checked my math, but I think I'm right. Since you are mixing the cold water with what is already there, it will just continually get cooler until you are barely raising the temp once all of the stored water is diluted with the incoming.

rheem or brad white

stay away form american water heaters, sears , state and
smith..... they willl all break your heart


get the Rheem unit or the BRAD white aand get them with heavy duty elements Stainless STEEL and you should be ok for a long time

recovery

If the heaters have the same wattage elements they will furnish the same amount of hot water once the initial stored hot water is gone, so a 40 gallon will supply slightly less than 10 more gallons before the two are equal.